1. Field of the Invention
Exemplary aspects of the present invention generally relate to an image forming apparatus, and more particularly, to an image forming apparatus that includes a lubricant applicator and a process cartridge using the same.
2. Description of the Background Art
An image forming process performed by an image forming apparatus using an electrophotographic method includes forming an electrostatic latent image on a photoreceptor serving as an image carrier through photoconductive development and adhering toner particles of colors corresponding to the electrostatic latent image using electrostatic force.
Such an electrophotographic image forming apparatus is generally equipped with a lubricant applicator that applies a lubricant to a surface of the photoreceptor, which is the main device for forming an image. The lubricant applicator is used in the image forming apparatus in an attempt to solve a problem that arises, for example, when a cleaning brush or a cleaning blade removes the toner adhering to the surface of the photoreceptor after image transfer.
Product life of the photoreceptor and an intermediate transfer belt depends on a level of deterioration due to mechanical friction with the cleaning brush and the cleaning blade. Therefore, in an effort to enhance the product life, the lubricant is applied to the surface of the photoreceptor and the intermediate transfer belt so that a friction coefficient can be reduced, thereby suppressing abrasion and thus extending photoreceptor product life.
In addition, the reduction of the friction coefficient of the photoreceptor surface eases removal of the toner residue adhering to the photoreceptor surface.
In other words, applying the lubricant to the photoreceptor surface makes it easier for the cleaning brush or the cleaning blade to remove the residual toner adhering to the photoreceptor or the intermediate transfer belt surface after a transfer process. Here, “residual toner” refers to that toner which has not been transferred to a recording medium or the like during the transfer process but remains on the photoreceptor or the intermediate transfer belt.
In recent years, a toner consisting of spherical particles produced by polymerization has come to be widely used. An advantage of such spherical toner is its uniform particle size distribution, which makes it possible to effectively reduce the particle size. As a result, image quality can be enhanced.
On the other hand, there is a drawback to such a toner. That is, the small size of the toner particles makes removal or cleaning of the residual toner from the photoreceptor difficult.
In light of the above, a technology that uses the lubricant applicator for applying the lubricant on the photoreceptor surface to improve cleaning of the photoreceptor becomes more important.
The lubricant is applied to the photoreceptor surface little by little in powder form. Specifically, as disclosed in Japanese Patent Laid-Open Application No. 2000-162881, a block-form lubricant is scraped and applied by an applicator such as a brush or the like.
As disclosed in Patent Publication No. 2859646, the lubricant can be supplied to the photoreceptor by externally adding the lubricant to the toner. However, where the lubricant is externally added to the toner and supplied to the photoreceptor, an amount supplied depends on an output image area. Consequently, it is difficult to stably supply the lubricant to an entire surface of the photoreceptor.
In terms of stably supplying the lubricant to the entire surface of the photoreceptor, a method in which a brush is used to scrape a solid lubricant that the brush then applies is preferable.
When the lubricant is applied to the photoreceptor surface, it is important to regulate both the amount and the state of the lubricant thus applied in order to prevent abrasion and enhance cleaning. For example, when lubricity is considered important, a certain amount of lubricant may be continuously supplied.
However, when the amount supplied becomes excessive, the excess lubricant may contaminate nearby devices such as a developing unit. Consequently, a charging amount of the toner may not be properly regulated.
Furthermore, in order to satisfy recent demand for a reduction of the size of a copier and a printer, the reduction of the size of components is important. Thus, it is preferable to minimize the size of the solid lubricant so that it is not larger than necessary.
Accordingly, several attempts have been made to regulate application of the lubricant on the photoreceptor. For example, a related art that regulates an application state of the lubricant applied to the photoreceptor serving as an image carrier is disclosed in Japanese Patent Laid-Open Application Hei-9-62163, which discloses ways in which a pressure of the solid lubricant on the photoreceptor and a linear velocity of an application brush contacting the solid lubricant are controlled.
Similarly, Japanese Patent Laid-Open Application 2000-75752 discloses ways in which an applied amount of the lubricant per unit of rotation of the photoreceptor is determined, and Japanese Patent Laid-Open Application 2002-244485 discloses ways in which a number of rotations of the lubricant application brush is regulated according to image forming information.
Furthermore, Japanese Patent Laid-Open Application 2002-351287 discloses an image forming apparatus which replaceably includes various kinds of engine units each having a nonvolatile memory and different functions so that a user does not need to repurchase the whole image forming apparatus when the user wishes to change only a performance of the image forming apparatus.
Such an image forming apparatus further includes a control mechanism that controls the performance of the image forming apparatus based on stored information of a storage mechanism in the engine unit mounted to the image forming apparatus. The user may change the performance characteristics of the apparatus, such as recording speed, resolution, and so forth, by replacing the engine unit with an engine unit with different performance characteristics without changing the main body of the image forming apparatus.
However, the above-described related arts do not indicate ways to improve sliding between a lubricant support member for supporting the lubricant in the lubricant applicator and a lubricant holder for storing the lubricant.
Consequently, there is such a problem that the solid lubricant cannot be pressed against the lubricant application brush, and thus the amount of the lubricant applied to the image carrier surface fluctuates.
When the amount of the lubricant applied fluctuates and is excessive, the nearby charging unit or other devices disposed nearby may easily be contaminated. On the other hand, when the applied amount of the lubricant is inadequate, the toner adheres to the image carrier surface and a phenomenon called filming may easily occur.